yurydelendik/playtone.html

## playtone.html
<!doctype html>

<html>

<head>

    <title></title>

    <script>

// Resample sound using linear interpolation for Web Audio due to
// http://code.google.com/p/chromium/issues/detail?id=73062
function AudioResampler(sourceRate, targetRate) {
  this.sourceRate = sourceRate;
  this.targetRate = targetRate;
  this.tail = [];
  this.sourceOffset = 0;
}
AudioResampler.prototype = {
  ondatarequested: function (e) { },
  getData: function (channelsData, count) {
    var k = this.sourceRate / this.targetRate;

    var offset = this.sourceOffset;
    var needed = Math.floor(count * k + offset + 1);
    var sourceData = [];
    for (var channel = 0; channel < channelsData.length; channel++)
      sourceData.push(new Float32Array(needed));
    var e = { data: sourceData, count: needed };
    this.ondatarequested(e);

    for (var channel = 0; channel < channelsData.length; channel++) {
      var data = channelsData[channel];
      var source = sourceData[channel];
      for (var j = 0; j < count; j++) {
        var i = j * k + offset;
        var i1 = Math.floor(i), i2 = Math.ceil(i);
        var source_i1 = i1 < 0 ? this.tail[channel] : source[i1];
        if (i1 === i2) {
          data[j] = source_i1;
        } else {
          var alpha = i - i1;
          data[j] = source_i1 * (1 - alpha) + source[i2] * alpha;
        }
      }
      this.tail[channel] = source[needed - 1];
    }
    this.sourceOffset = (count * k + offset) - needed;
  }
};

function WebAudioChannel(sampleRate, channels) {
  var context;
  if (typeof AudioContext !== 'undefined')
    context = new AudioContext();
  else
    context = new webkitAudioContext();
  this.context = context;
  this.contextSampleRate = context.sampleRate || 44100;

  this.channels = channels;
  this.sampleRate = sampleRate;
  if (this.contextSampleRate != sampleRate) {
    this.resampler = new AudioResampler(sampleRate, this.contextSampleRate);
    this.resampler.ondatarequested = function (e) {
      this.requestData(e.data, e.count);
    }.bind(this);
  }
}
WebAudioChannel.prototype = {
  ondatarequested: function () {},
  start: function () {
    var source = this.context.createScriptProcessor ?
      this.context.createScriptProcessor(512, 0, this.channels) :
      this.context.createJavaScriptNode(512, 0, this.channels);
    var self = this;
    source.onaudioprocess = function(e) {
      var channelsData = [];
      for (var i = 0; i < self.channels; i++)
        channelsData.push(e.outputBuffer.getChannelData(i));
      var count = channelsData[0].length;
      if (self.resampler) {
        self.resampler.getData(channelsData, count);
      } else {
        var e = { data: channelsData, count: count };
        self.requestData(channelsData, count);
      }
    };

    source.connect(this.context.destination);
    this.source = source;
  },
  stop: function () {
    this.source.disconnect(this.context.destination);
  },
  requestData: function (channelsData, count) {
    var channels = this.channels;
    var buffer = new Float32Array(count * channels);
    var e = { data: buffer, count: buffer.length };
    this.ondatarequested(e);

    for (var j = 0, p = 0; j < count; j++) {
      for (var i = 0; i < channels; i++)
        channelsData[i][j] = buffer[p++];
    }
  }
};
WebAudioChannel.isSupported = (function() {
  return typeof AudioContext !== 'undefined' ||
         typeof webkitAudioContext != 'undefined';
})();

// from https://wiki.mozilla.org/Audio_Data_API
function AudioDataChannel(sampleRate, channels) {
  this.sampleRate = sampleRate;
  this.channels = channels;
}
AudioDataChannel.prototype = {
  start: function () {
    var sampleRate = this.sampleRate;
    var channels = this.channels;
    var self = this;

    // Initialize the audio output.
    var audio = new Audio();
    audio.mozSetup(channels, sampleRate);

    var currentWritePosition = 0;
    var prebufferSize = sampleRate * channels / 2; // buffer 500ms
    var tail = null, tailPosition;

    // The function called with regular interval to populate
    // the audio output buffer.
    this.interval = setInterval(function() {
      var written;
      // Check if some data was not written in previous attempts.
      if(tail) {
        written = audio.mozWriteAudio(tail.subarray(tailPosition));
        currentWritePosition += written;
        tailPosition += written;
        if(tailPosition < tail.length) {
          // Not all the data was written, saving the tail...
          return; // ... and exit the function.
        }
        tail = null;
      }

      // Check if we need add some data to the audio output.
      var currentPosition = audio.mozCurrentSampleOffset();
      var available = currentPosition + prebufferSize - currentWritePosition;
      available -= available % channels; // align to channels count
      if(available > 0) {
        // Request some sound data from the callback function.
        var soundData = new Float32Array(available);
        self.requestData(soundData, available);

        // Writting the data.
        written = audio.mozWriteAudio(soundData);
        if(written < soundData.length) {
          // Not all the data was written, saving the tail.
          tail = soundData;
          tailPosition = written;
        }
        currentWritePosition += written;
      }
    }, 100);
  },
  stop: function () {
    clearInterval(this.interval);
  },
  requestData: function (data, count) {
    this.ondatarequested({data: data, count: count});
  }
};
AudioDataChannel.isSupported = (function () {
  return 'mozSetup' in (new Audio);
})();

var sourceRate = 48000;

var a = new Float32Array(100000);
for (var i = 0; i < 50000; i++) {
  a[i] = Math.sin(Math.PI * 2 / sourceRate * i * 440) / 4;
}
var ai = 0;

var channels = 1;
var audio;
if (WebAudioChannel.isSupported)
  audio = new WebAudioChannel(sourceRate, channels);
else if (AudioDataChannel.isSupported)
  audio = new AudioDataChannel(sourceRate, channels);
else
  throw 'unsupported';

audio.ondatarequested = function (e) {
  var channels = e.data;
  for (var j = 0; j < e.count; j++) {
    e.data[j] = a[ai++];
    if (ai > a.length) ai = 0;
  }
};

function playSound() {
  audio.start();
}

    </script>
</head>

<body>

<button onclick="playSound();">test</button>

</body>

</html>
	<!doctype html>

	<html>

	<head>

	<title></title>

	<script>

	// Resample sound using linear interpolation for Web Audio due to
	// http://code.google.com/p/chromium/issues/detail?id=73062
	function AudioResampler(sourceRate, targetRate) {
	this.sourceRate = sourceRate;
	this.targetRate = targetRate;
	this.tail = [];
	this.sourceOffset = 0;
	}
	AudioResampler.prototype = {
	ondatarequested: function (e) { },
	getData: function (channelsData, count) {
	var k = this.sourceRate / this.targetRate;

	var offset = this.sourceOffset;
	var needed = Math.floor(count * k + offset + 1);
	var sourceData = [];
	for (var channel = 0; channel < channelsData.length; channel++)
	sourceData.push(new Float32Array(needed));
	var e = { data: sourceData, count: needed };
	this.ondatarequested(e);

	for (var channel = 0; channel < channelsData.length; channel++) {
	var data = channelsData[channel];
	var source = sourceData[channel];
	for (var j = 0; j < count; j++) {
	var i = j * k + offset;
	var i1 = Math.floor(i), i2 = Math.ceil(i);
	var source_i1 = i1 < 0 ? this.tail[channel] : source[i1];
	if (i1 === i2) {
	data[j] = source_i1;
	} else {
	var alpha = i - i1;
	data[j] = source_i1 * (1 - alpha) + source[i2] * alpha;
	}
	}
	this.tail[channel] = source[needed - 1];
	}
	this.sourceOffset = (count * k + offset) - needed;
	}
	};

	function WebAudioChannel(sampleRate, channels) {
	var context;
	if (typeof AudioContext !== 'undefined')
	context = new AudioContext();
	else
	context = new webkitAudioContext();
	this.context = context;
	this.contextSampleRate = context.sampleRate \|\| 44100;

	this.channels = channels;
	this.sampleRate = sampleRate;
	if (this.contextSampleRate != sampleRate) {
	this.resampler = new AudioResampler(sampleRate, this.contextSampleRate);
	this.resampler.ondatarequested = function (e) {
	this.requestData(e.data, e.count);
	}.bind(this);
	}
	}
	WebAudioChannel.prototype = {
	ondatarequested: function () {},
	start: function () {
	var source = this.context.createScriptProcessor ?
	this.context.createScriptProcessor(512, 0, this.channels) :
	this.context.createJavaScriptNode(512, 0, this.channels);
	var self = this;
	source.onaudioprocess = function(e) {
	var channelsData = [];
	for (var i = 0; i < self.channels; i++)
	channelsData.push(e.outputBuffer.getChannelData(i));
	var count = channelsData[0].length;
	if (self.resampler) {
	self.resampler.getData(channelsData, count);
	} else {
	var e = { data: channelsData, count: count };
	self.requestData(channelsData, count);
	}
	};

	source.connect(this.context.destination);
	this.source = source;
	},
	stop: function () {
	this.source.disconnect(this.context.destination);
	},
	requestData: function (channelsData, count) {
	var channels = this.channels;
	var buffer = new Float32Array(count * channels);
	var e = { data: buffer, count: buffer.length };
	this.ondatarequested(e);

	for (var j = 0, p = 0; j < count; j++) {
	for (var i = 0; i < channels; i++)
	channelsData[i][j] = buffer[p++];
	}
	}
	};
	WebAudioChannel.isSupported = (function() {
	return typeof AudioContext !== 'undefined' \|\|
	typeof webkitAudioContext != 'undefined';
	})();

	// from https://wiki.mozilla.org/Audio_Data_API
	function AudioDataChannel(sampleRate, channels) {
	this.sampleRate = sampleRate;
	this.channels = channels;
	}
	AudioDataChannel.prototype = {
	start: function () {
	var sampleRate = this.sampleRate;
	var channels = this.channels;
	var self = this;

	// Initialize the audio output.
	var audio = new Audio();
	audio.mozSetup(channels, sampleRate);

	var currentWritePosition = 0;
	var prebufferSize = sampleRate * channels / 2; // buffer 500ms
	var tail = null, tailPosition;

	// The function called with regular interval to populate
	// the audio output buffer.
	this.interval = setInterval(function() {
	var written;
	// Check if some data was not written in previous attempts.
	if(tail) {
	written = audio.mozWriteAudio(tail.subarray(tailPosition));
	currentWritePosition += written;
	tailPosition += written;
	if(tailPosition < tail.length) {
	// Not all the data was written, saving the tail...
	return; // ... and exit the function.
	}
	tail = null;
	}

	// Check if we need add some data to the audio output.
	var currentPosition = audio.mozCurrentSampleOffset();
	var available = currentPosition + prebufferSize - currentWritePosition;
	available -= available % channels; // align to channels count
	if(available > 0) {
	// Request some sound data from the callback function.
	var soundData = new Float32Array(available);
	self.requestData(soundData, available);

	// Writting the data.
	written = audio.mozWriteAudio(soundData);
	if(written < soundData.length) {
	// Not all the data was written, saving the tail.
	tail = soundData;
	tailPosition = written;
	}
	currentWritePosition += written;
	}
	}, 100);
	},
	stop: function () {
	clearInterval(this.interval);
	},
	requestData: function (data, count) {
	this.ondatarequested({data: data, count: count});
	}
	};
	AudioDataChannel.isSupported = (function () {
	return 'mozSetup' in (new Audio);
	})();

	var sourceRate = 48000;

	var a = new Float32Array(100000);
	for (var i = 0; i < 50000; i++) {
	a[i] = Math.sin(Math.PI * 2 / sourceRate * i * 440) / 4;
	}
	var ai = 0;

	var channels = 1;
	var audio;
	if (WebAudioChannel.isSupported)
	audio = new WebAudioChannel(sourceRate, channels);
	else if (AudioDataChannel.isSupported)
	audio = new AudioDataChannel(sourceRate, channels);
	else
	throw 'unsupported';

	audio.ondatarequested = function (e) {
	var channels = e.data;
	for (var j = 0; j < e.count; j++) {
	e.data[j] = a[ai++];
	if (ai > a.length) ai = 0;
	}
	};

	function playSound() {
	audio.start();
	}

	</script>
	</head>

	<body>

	<button onclick="playSound();">test</button>

	</body>

	</html>